A control method and system for enhancing the synchronization stability of a double-fed fan

Abstract

The invention discloses a control method and system for enhancing the synchronous stability of a double-fed fan, belonging to the technical field of the double-fed fan. Specifically include: Once a severe voltage drop in the grid is detected, the rotor current control mode of the double-fed fan will be switched immediately. During the fault period, the rotor q-axis reference current is obtained according to the grid voltage drop depth and the grid code standard, and the rotor d-axis current is determined by the active power The calculation of the loop is obtained, where the active power reference command is determined by the real-time detected active power consumed by the grid resistance. The present invention can still ensure the synchronous stability of the doubly-fed system when the frequency of the power grid changes during a fault, and only needs to increase the amount of detection of the change of the resistance of the power grid when a fault occurs, has fewer detection variables, and can realize the system frequency under severe power grid faults The doubly-fed wind turbine still has the ability to synchronize with the grid when changing, and has the advantages of various control objectives such as dynamic reactive power compensation, which greatly enhances the synchronization stability of the doubly-fed wind turbine under severe voltage drop.

Description

technical field [0001] The invention belongs to the technical field of double-fed fans, and more specifically relates to a control method and system for enhancing the synchronous stability of double-fed fans. Background technique [0002] Short-circuit faults are common accidents in power systems. However, as the proportion of new energy power generation equipment in the power system increases, the port voltage drop caused by short-circuit faults will seriously threaten the stable operation of new energy power generation equipment. Compared with other new energy power generation equipment, the fault ride-through difficulty of doubly-fed wind generator is more difficult due to the limitation of converter capacity. In practical applications, the double-fed wind turbine usually uses a crowbar to withstand the transient current during the voltage drop immediately after detecting a grid fault, thereby effectively avoiding overvoltage and overcurrent of the rotor-side converter. ...

AI Technical Summary

Problems solved by technology

[0004] Aiming at the defects of the existing technology, the present invention proposes an enhanced double-fed fan to solve the problems that the existing technology cannot maintain the synchronous stability of the doubly-fed fan when the system frequency changes and the grid impedance estimation is inaccurate under severe power grid voltage drop conditions. The control method and system for the synchronous stability of the fan feeder can be applied to deep power grid faults, have fewer detection variables, and are simple and feasible

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